Pneumatic measuring devices are generally known and are used, for example in dimensional measurement technology, for carrying out contactless measurements with a very high resolution of up to 0.1 μm, for example. In particular, pneumatic measuring devices may be used to perform static and/or dynamic measurements of geometric properties such as straightness, flatness, roundness, cylindrical shape, profile, angle, orthogonality, parallelism, position, concentricity, symmetry, and true running.
A measuring head of the type in question of a pneumatic measuring device for measuring a workpiece is known from U.S. Pat. No. 2,846,871, having a base element in which a first flow channel for connecting a compressed air source to a measuring nozzle is formed, the first flow channel having a constricted area with at least one cross-sectional constriction. The measuring head has a second flow channel for connecting the constricted area to a pressure transducer.
A similar measuring head is also known from U.S. Pat. No. 2,513,374.
A measuring device which operates according to the Venturi principle is known from U.S. Pat. No. 1,940,921.
A measuring head of a pneumatic measuring device for measuring a workpiece is known from DE 10223592 A1 (corresponding to U.S. Pat. No. 6,647,808 B2 and JP 002002 357410A), having a base element in which a first flow channel for connecting a compressed air source to a measuring nozzle is formed, the first flow channel having at least one cross-sectional constriction in a constricted area. The measuring head also has a second flow channel for connecting the constricted area to a measuring transducer.
An air nozzle in the form of a valve nozzle is known from DE 10 2007 028141 A1, which is configured as a substantially tubular component which is divided into a front, first section and a rear, second section with respect to the direction of an air flow, the second section being connected to the first section 8 via a constricted area 10 (narrowest cross section), and in addition the constricted area being connectable to a measuring apparatus via a flow channel, thus allowing the pressure prevailing in the constricted area to be reduced.
A pneumatic measuring device for detecting irregularities in the topography of surfaces of rotationally symmetrical components in particular is known from DE 20 2006 010164 U1, having a nozzle, provided in a housing. for generating a vortex-like gas flow which is directed from the nozzle opening onto the surface of the component to be investigated, and at least one acoustic detector or microphone for detecting the sound generated by the gas flow.